The field of the invention is protective helmets, for motorcyclists and others, to guard the wearer against head injuries. More particularly, the field is that of helmet assembly, of inserting rigid liners into helmet shells made of fiberglass or a transparent plastic which are color coated on their inside surface. The rigid liner used in such a shell is a thick, stiff material usually molded from expanded polystyrene.
At present, liners are forced into the shell by hand and then adjusted or centered to the proper position, also by hand. This method of insertion and adjustment requires a substantial amount of physical force and sometimes causes scratches of the coating on the inside of the shell due to the tight fit and abrasive qualities of the contacting surfaces. Some helmet shells are made of hand-laid fiberglass which is very abrasive. Other shells are painted with a metal flake paint on the inside surface which is also very abrasive. Such damage is avoided by this invention, and in addition, the time required for insertion and centering of the liner is substantially reduced.